315589

Properties

Appears in sequences

• a(n) = a(1) + a(2) + ... + a(n-1) - a(m) for n >= 4, where m = n - 1 - 2^p and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = a(2) = 1 and a(3) = 4.at n=19A049898
• a(n) is the smallest positive integer k such that the last n digits of 2^k are 1 or 2.at n=8A147884
• a(n) is the smallest positive integer k such that the last n digits of 2^k are 1 or 2.at n=9A147884
• Least prime p such that the first n primes divide p^2-1.at n=7A214089
• a(n) is the number of squares <= 10^n that are not higher powers, i.e., terms of A076467.at n=10A378168
• Prime numbersat n=27242